Along with user's increasing demand for a higher security reliability and a higher processing capacity of the network, the operator must introduce enough capacity and various diversity means to the network when designing the network at the beginning in order to provide enough service ability for the users, reduce the influence of troubles and raise the ability of preferential recovery, double access and multi-routing of the network, which ensures normal service provision and enhances the users' satisfaction with the service. But on the other hand, if core control equipment or core processing equipment adopts an active/standby mode, not only the cost of networking and maintaining will be increased, but also a heavy resource waste will be caused as a result of the idle state of the stand-by equipment.
So, under a comprehensive consideration of several factors, such as the integrated level, the cost, disaster tolerance capability and network security of equipment, etc, the dual-homing concept is introduced, whose function lies in preventing large area paralyzed systems or offering a mechanism of communication promptly when an accident suddenly appears, offering a fast recovery ability of equipment communication when an unusual situation takes place. For example: a recovery mechanism including a urgent communication can offer 80%.about.90% ability of the communication recovery. The dual-homing thereinafter refers to a special network connection, by which each network entity which needs the switching control center to provide a service is connected with two switching control centers at the same time, the two switching control centers are standby for each other, every network entity can be provided with the service by either of the two joined switching control centers. Generally, each network entity has a homing switching control center of itself. In normal state, each switching control center manages one or more network entities of its own, i.e., each switching control center provides services for the network entities of its own, when any switching control center breaks down, the standby switching control center will take over all the network entities under the switching control center that has broken down. The switching control center refers to a network equipment at a core position in a network, for example: a softswitch, a Mobile Switching Center (MSC) server, etc, the processing capability and the disaster tolerance capability which are provided by the dual-homing technique have much to do with the networking and the implementation of the dual-homing.
The communication networks used at present can be divided into wired communication networks and wireless communication networks, a typical representative of the latest wired communication network is Next Generation Network (NGN). The NGN is a brand-new network incorporating voice, data, fax and video services into an organic whole, which has achieved the separation of call control and service bearer; a typical representative of the latest wireless communication network is the third generation (3G) mobile communication network. The user capacity of the NGN and the 3G network are both very large, the requirements for the communication reliability and the network processing ability are also very high, so, the dual-homing mode can be introduced to the networking of NGN and 3G networks. Specifically, in the networking of NGN, the softswitch is at an extremely core and important position, between which no default standby relation exists on the networking level. In order to make the service handled by the softswitch breaking down be taken over automatically by its standby softswitch and to minimize the service interruption under the circumstances of the softswitch breaking down, an unusual disaster, or a hardware upgrading, it is needed to realize the dual-homing of the softswitch so as to enhance the network reliability. The dual-homing here means that two softswitches are mutually standby on the networking level, as shown in FIG. 1. In this way, a softswitch at the dual-homing position is able to take over the service of the other softswitch which shuts down or is out of service.
In the NGN shown in FIG. 1, two softswitches are mutually standby softswitches, each softswitch is configured with an Originating Point Code (OPC), and a Public Switched Telephone Network (PSTN) connects the softswitch to access the network through a Media Gateway (MGW). The softswitch and the MGW are connected and the data are transmitted between them through a trunk signaling link. In the normal state, each softswitch serves the MGW of its own separately, if a softswitch is shut down or in other breakdown situations, the MGW connected to the softswitch needs register to the standby softswitch again, so as to ensure the service continuity. A signaling point is a node processing the control information in the signaling network.
Similarly, in a 3G core network, the MSC Server is at an extremely core and important position, between which no default standby relation exists on the networking level. In order to make the service handled by the breaking-down MSC Server can be taken over automatically by its standby MSC Server and to minimize the service interruption under the circumstances of an MSC Server breaking down, a unusual disaster or a hardware upgrading, it is needed to realize the dual-homing to the MSC Server so as to enhance the network reliability. The dual-homing here means that two MSC Servers are mutually standby on the networking level, as shown in FIG. 2, in such a way that an MSC Server at the dual-homing position is able to take over the service of the other MSC Server that has been inactive or has been in the out-of-service state.
The 3G network is shown in FIG. 2, two MSC Servers are mutually standby, each MSC Server is configured with the OPC, and a Base Station Controller (BSC)/Radio Network Controller (RNC) connects the MSC Server to access the network through the MGW. The MGW and the MSC Server connects with each other and transmits data between them through trunk signaling links. In the normal state, each MSC Server serves the MGW of its own separately, if some MSC Server equipment shuts down or in other breakdown situations, the MGW connected to the MSC Server that shuts down or breaks down needs to register to the standby MSC Server again so as to ensure the service continuity.